diff --git a/pylons_app/model/user_model.py b/pylons_app/model/user_model.py
--- a/pylons_app/model/user_model.py
+++ b/pylons_app/model/user_model.py
@@ -36,8 +36,11 @@ class DefaultUserException(Exception):pa
 
 class UserModel(object):
 
-    def __init__(self):
-        self.sa = Session() 
+    def __init__(self, sa=None):
+        if not sa:
+            self.sa = Session()
+        else:
+            self.sa = sa
     
     def get_default(self):
         return self.sa.query(User).filter(User.username == 'default').scalar()